The divorce rate is about the same for JW's as the general population.
I was sitting at a Watchtower study on marriage where they were basically bragging about the power of "God's Word" to hold marriages together.
I got bored and started listing in the margins every wedding I had been to in the previous 40 years. Witnesses get to go to a lot of weddings.
I listed a little over 50 weddings. Then I crossed out all those that were no longer married. Almost exactly half were no longer together.
A small but unsurprising survey.
The biggest factor is how two personalities get along after the sexual heat is off. Opposites attract but they don't last. The other extreme where two people are very similar doesn't work because there often isn't enough passion. That leaves a middle area where the people are enough alike to get along and different enough to generate some heat.
Marriage really is a 50/50 proposition. Half work well enough and half fail.